第110回薬剤師国家試験

$\begin{tikzpicture}[xscale=1/80,yscale=1,declare function = {AA0=1000;TA=66;TB=6;AA(\x)=AA0*2^(-\x/TA);AB(\x)=TA/(TA-TB)*(2^(-\x/TA)-2^(-\x/TB))*AA0;}]\draw[thick,< - >,>=stealth] (0,4) node[right]{\scriptsize 放射能の常用対数}-- (0,0) node[below left=-1mm]{\scriptsize 0} -- (480,0) node[below=2mm,pos=0.5]{\scriptsize 時間／d};\draw[semithick,smooth,domain=0:480,teal] plot(\x,{ln(AA(\x))/ln(10)});\draw[semithick,samples=200,domain=0.008:480,blue] plot(\x,{ln(AB(\x))/ln(10)});\foreach \x/\t in {120/5,240/10,360/15,480/20} \node at (\x,-0.15) {\scriptsize \t};\node [teal] at (360,0.9) {\scriptsize $^{99}\rm Mo$ の放射能}; \node [blue] at (360,1.8) {\scriptsize $^{99\rm m}\rm Tc$ の放射能}; \end{tikzpicture}$

\begin{tikzpicture}[xscale=1/80,yscale=1,
declare function = {
AA0=1000;
TA=66;
TB=6;
AA(\x)=AA0*2^(-\x/TA);
AB(\x)=TA/(TA-TB)*(2^(-\x/TA)-2^(-\x/TB))*AA0;
}]
\draw[thick,< - >,>=stealth] (0,4) node[right]{\scriptsize 放射能の常用対数}-- (0,0) node[below left=-1mm]{\scriptsize 0} -- (480,0) node[below=2mm,pos=0.5]{\scriptsize 時間／d};
\draw[semithick,smooth,domain=0:480,teal] plot(\x,{ln(AA(\x))/ln(10)});
\draw[semithick,samples=200,domain=0.008:480,blue] plot(\x,{ln(AB(\x))/ln(10)});
%\node [left] at (0,3) {\scriptsize $\log A_{\rm A_0}$};
\foreach \x/\t in {120/5,240/10,360/15,480/20}
 \node at (\x,-0.15) {\scriptsize \t};
\node [teal] at (360,0.9) {\scriptsize $^{99}\rm Mo$ の放射能}; 
\node [blue] at (360,1.8) {\scriptsize $^{99\rm m}\rm Tc$ の放射能}; 
\end{tikzpicture}